Targeting the hERG1 and β1 integrin complex for cancer treatment

INTRODUCTION

Despite great advances, novel therapeutic targets and strategies are still needed, in particular for some carcinomas in the metastatic stage (breast cancer, colorectal cancer, pancreatic ductal adenocarcinoma and the clear cell renal carcinoma). Ion channels may be considered good cancer biomarkers and targets for antineoplastic therapy. These concepts are particularly relevant considering the hERG1 potassium channel as a novel target for antineoplastic therapy.

AREAS COVERED

A great deal of evidence demonstrates that hERG1 is aberrantly expressed in human cancers, in particular in aggressive carcinomas. A relevant cornerstone was the discovery that, in cancer cells, the channel is present in a very peculiar conformation, strictly bound to the β1 subunit of integrin receptors. The hERG1/β1 integrin complex does not occur in the heart. Starting from this evidence, we developed a novel single chain bispecific antibody (scDb-hERG1-β1), which specifically targets the hERG1/β1 integrin complex and exerts antineoplastic effects in preclinical experiments.

EXPERT OPINION

Since hERG1 blockade cannot be pursued for antineoplastic therapy due to the severe cardiac toxic effects (ventricular arrhythmias) that many hERG1 blockers exert, different strategies must be identified to specifically target hERG1 in cancer. The targeting of the hERG1/β1 integrin complex through the bispecific antibody scDb-hERG1-β1 can overcome such hindrances.

Integrins regulate hERG1 dynamics by girdin-dependent Gαi3: signaling and modeling in cancer cells

The hERG1 potassium channel is aberrantly over expressed in tumors and regulates the cancer cell response to integrin-dependent adhesion. We unravel a novel signaling pathway by which integrin engagement by the ECM protein fibronectin promotes hERG1 translocation to the plasma membrane and its association with β1 integrins, by activating girdin-dependent Gαi3 proteins and protein kinase B (Akt). By sequestering hERG1, β1 integrins make it avoid Rab5-mediated endocytosis, where unbound channels are degraded. The cycle of hERG1 expression determines the resting potential (Vrest) oscillations and drives the cortical f-actin dynamics and thus cell motility. To interpret the slow biphasic kinetics of hERG1/β1 integrin interplay, we developed a mathematical model based on a generic balanced inactivation-like module. Integrin-mediated cell adhesion triggers two contrary responses: a rapid stimulation of hERG1/β1 complex formation, followed by a slow inhibition which restores the initial condition. The protracted hERG1/β1 integrin cycle determines the slow time course and cyclic behavior of cell migration in cancer cells.

Immunosuppressive effects of new thiophene-based KV1.3 inhibitors

Voltage-gated potassium channel KV1.3 inhibitors have been shown to be effective in preventing T-cell proliferation and activation by affecting intracellular Ca2+ homeostasis. Here, we present the structure-activity relationship, KV1.3 inhibition, and immunosuppressive effects of new thiophene-based KV1.3 inhibitors with nanomolar potency on K+ current in T-lymphocytes and KV1.3 inhibition on Ltk- cells. The new KV1.3 inhibitor trans-18 inhibited KV1.3 -mediated current in phytohemagglutinin (PHA)-activated T-lymphocytes with an IC50 value of 26.1 nM and in mammalian Ltk- cells with an IC50 value of 230 nM. The KV1.3 inhibitor trans-18 also had nanomolar potency against KV1.3 in Xenopus laevis oocytes (IC50 = 136 nM). The novel thiophene-based KV1.3 inhibitors impaired intracellular Ca2+ signaling as well as T-cell activation, proliferation, and colony formation.

High throughput clone screening on overexpressed hERG1 and Kv1.3 potassium channels using ion channel reader (ICR) label free technology

Pharmacological studies aimed at the development of newly synthesized drugs directed against ion channels (as well as genetic studies of ion channel mutations) involve the development and use of transfected cells. However, the identification of the best clone, in terms of transfection efficiency, is often a time consuming procedure when performed through traditional methods such as manual patch-clamp. On the other hand, the use of other faster techniques, such as for example the IF, are not informative on the effective biological functionality of the transfected ion channel(s). In the present work, we used the high throughput automated ion channel reader (ICR) technology (ICR8000 Aurora Biomed Inc.) that combine atomic absorption spectroscopy with a patented microsampling process to accurately measure ion flux in cell-based screening assays. This technology indeed helped us to evaluate the transfection efficiency of hERG1 and hKv1.3 channels respectively on the HEK-293 and CHO cellular models. Moreover, as proof of the validity of this innovative method, we have corroborated these data with the functional characterization of the potassium currents carried out by the same clones through patch-clamp recordings. The results obtained in our study are promising and represent a valid methodological strategy to screen a large number of clones simultaneously and to pharmacologically evaluate their functionality within an extremely faster timeframe.

Cardiac safety assessment of a novel recombinant bispecific antibody targeting the ether-à-go-go related gene 1 (hERG1)-β1 integrin macromolecular complex

Introduction: In the last decades, mounting evidence has pointed out the human ether-á-go-go-related gene (hERG1) potassium channel as a novel biomarker in human cancers. However, hERG1 sustains the cardiac repolarizing current IKr and its blockade can induce a prolonged QT interval at the ECG, which increases the risk of life-threatening arrhythmias. This represents a major hindrance for targeting hERG1 for antineoplastic therapeutic purposes. Based on our discovery that hERG1 resides in a macromolecular complex with the β1 subunit of integrin adhesion receptors only in tumors, and not in the heart, we generated (and patented WO2019/015936) a novel engineered, single chain, bispecific antibody in the format of a diabody (scDb-hERG1-β1). This antibody has been proven to target with high affinity the hERG1/β1 integrin complex and to exert a good antineoplastic activity in preclinical mouse models. Methods: In the present study, we evaluated the cardiac safety of the scDb-hERG1-β1, determining the action potential duration (APD) of human cardiomyocytes, either atrial (from valve-disease patients) or ventricular (from aortic stenosis patients). Cardiac cells were incubated in vitro with i) the scDb-hERG1-β1, ii) the full length anti-hERG1 monoclonal antibody (mAb-hERG1) and iii) its single chain Fragment variable derivative (scFv-hERG1), from which the scDb-hERG1-β1 was assembled. All the tests were performed before and after treatment with the specific hERG1 blocker E4031. In addition, we have performed preliminary experiments, analyzing the effects of the scDb-hERG1/β1 in vivo measuring the QT interval length of the surface ECG after its injection intravenously in farm-pigs. Results: The scDb-hERG1-β1 did not produce any lengthening of APD compared to control (vehicle) conditions, either in atrial or ventricular cardiomyocytes, whereas both the hERG1-mAb and the scFv-hERG1 produced a significant APD prolongation. The addition of E4031 further prolonged APD. The scDb-hERG1-β1 did not produce any alterations of the QT (and QTc) interval values, once injected intravenously in farm pigs. Discussion: Overall, the above evidences plead for the cardiac safety of the scDb-hERG1-β1, suggesting that an application of this antibody for anti-cancer therapy will be untainted by cardiotoxicity.

Expression of the ether-a-gò-gò-related gene 1 channel during B and T lymphocyte development: role in BCR and TCR signaling

The functional relevance of K+ and Ca2+ ion channels in the "Store Operated Calcium Entry" (SOCE) during B and T lymphocyte activation is well proven. However, their role in the process of T- and B- cell development and selection is still poorly defined. In this scenario, our aim was to characterize the expression of the ether à-go-go-related gene 1 (ERG1) and KV1.3 K+ channels during the early stages of mouse lymphopoiesis and analyze how they affect Ca2+signaling, or other signaling pathways, known to mediate selection and differentiation processes of lymphoid clones. We provide here evidence that the mouse (m)ERG1 is expressed in primary lymphoid organs, bone marrow (BM), and thymus of C57BL/6 and SV129 mice. This expression is particularly evident in the BM during the developmental stages of B cells, before the positive selection (large and small PreB). mERG1 is also expressed in all thymic subsets of both strains, when lymphocyte positive and negative selection occurs. Partially overlapping results were obtained for KV1.3 expression. mERG1 and KV1.3 were expressed at significantly higher levels in B-cell precursors of mice developing an experimental autoimmune encephalomyelitis (EAE). The pharmacological blockage of ERG1 channels with E4031 produced a significant reduction in intracellular Ca2+ after lymphocyte stimulation in the CD4+ and double-positive T-cell precursors' subsets. This suggests that ERG1 might contribute to maintaining the electrochemical gradient responsible for driving Ca2+ entry, during T-cell receptor signaling which sustains lymphocyte selection checkpoints. Such role mirrors that performed by the shaker-type KV1.3 potassium channel during the activation process of mature lymphocytes. No effects on Ca2+ signaling were observed either in B-cell precursors after blocking KV1.3 with PSORA-4. In the BM, the pharmacological blockage of ERG1 channels produced an increase in ERK phosphorylation, suggesting an effect of ERG1 in regulating B-lymphocyte precursor clones' proliferation and checkpoint escape. Overall, our results suggest a novel physiological function of ERG1 in the processes of differentiation and selection of lymphoid precursors, paving the way to further studies aimed at defining the expression and role of ERG1 channels in immune-based pathologies in addition to that during lymphocyte neoplastic transformation.

Corrigendum to "Transcriptomic data of Bevacizumab-adapted colorectal adenocarcinoma cells HCT-116" [Data In Brief, Volume 48, (Available online 17 March 2023) 1-9/Article 109069]

[This corrects the article DOI: 10.1016/j.dib.2023.109069.].

Evaluation of RAS Mutational Status in Liquid Biopsy to Monitor Disease Progression in Metastatic Colorectal Cancer Patients

In this study we evaluated both~ K- and N-RAS mutations in plasma samples from patients with metastatic colorectal cancer by means of the BEAMing technology, and we assessed their diagnostic performance compared to RAS analyses performed on tissue. The sensitivity of BEAMing in identifying KRAS mutations was of 89.5%, with a fair specificity. The agreement with tissue analysis was moderate. The sensitivity for NRAS was high with a good specificity, and the agreement between tissue analysis and BEAMing was fair. Interestingly, significantly higher mutant allele fraction (MAF) levels were detected in patients with G2 tumors, liver metastases, and in those who did not receive surgery. NRAS MAF level was significantly higher in patients with mucinous adenocarcinoma and for those with lung metastases. A sharp increase in the MAF values was observed in patients who moved towards disease progression. More strikingly, molecular progression always anticipated the radiological one in these patients. These observations pave the way to the possibility of using liquid biopsy to monitor patients during treatment, and to enable oncologists to anticipate interventions compared to radiological analyses. This will allow time to be saved and ensure a better management of metastatic patients in the near future.

Combination Therapy with a Bispecific Antibody Targeting the hERG1/β1 Integrin Complex and Gemcitabine in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) represents an unmet medical need. Difficult/late diagnosis as well as the poor efficacy and high toxicity of chemotherapeutic drugs result in dismal prognosis. With the aim of improving the treatment outcome of PDAC, we tested the effect of combining Gemcitabine with a novel single chain bispecific antibody (scDb) targeting the cancer-specific hERG1/β1 integrin complex. First, using the scDb (scDb-hERG1-β1) in immunohistochemistry (IHC), Western blot (WB) analysis and immunofluorescence (IF), we confirmed the presence of the hERG1/β1 integrin complex in primary PDAC samples and PDAC cell lines. Combining Gemcitabine with scDb-hERG1-β1 improved its cytotoxicity on all PDAC cells tested in vitro. We also tested the combination treatment in vivo, using an orthotopic xenograft mouse model involving ultrasound-guided injection of PDAC cells. We first demonstrated good penetration of the scDb-hERG1-β1 conjugated with indocyanine green (ICG) into tumour masses by photoacoustic (PA) imaging. Next, we tested the effects of the combination at either therapeutic or sub-optimal doses of Gemcitabine (25 or 5 mg/kg, respectively). The combination of scDb-hERG1-β1 and sub-optimal doses of Gemcitabine reduced the tumour masses to the same extent as the therapeutic doses of Gemcitabine administrated alone; yielded increased survival; and was accompanied by minimised side effects (toxicity). These data pave the way for a novel therapeutic approach to PDAC, based on the combination of low doses of a chemotherapeutic drug (to minimize adverse side effects and the onset of resistance) and the novel scDb-hERG1-β1 targeting the hERG1/β1 integrin complex as neoantigen.

Combined Inhibition of Smoothened and the DNA Damage Checkpoint WEE1 Exerts Antitumor Activity in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is characterized by resistance to chemotherapy and a poor prognosis. Therefore, treatments that can effectively suppress tumor growth are urgently needed. Aberrant activation of hedgehog (HH) signaling has been implicated in several cancers, including those of the hepatobiliary tract. However, the role of HH signaling in intrahepatic CCA (iCCA) has not been completely elucidated. In this study, we addressed the function of the main transducer Smoothened (SMO) and the transcription factors (TFs) GLI1 and GLI2 in iCCA. In addition, we evaluated the potential benefits of the combined inhibition of SMO and the DNA damage kinase WEE1. Transcriptomic analysis of 152 human iCCA samples showed increased expression of GLI1, GLI2, and Patched 1 (PTCH1) in tumor tissues compared with nontumor tissues. Genetic silencing of SMO, GLI1, and GLI2 inhibited the growth, survival, invasiveness, and self-renewal of iCCA cells. Pharmacologic inhibition of SMO reduced iCCA growth and viability in vitro, by inducing double-strand break DNA damage, leading to mitotic arrest and apoptotic cell death. Importantly, SMO inhibition resulted in the activation of the G2-M checkpoint and DNA damage kinase WEE1, increasing the vulnerability to WEE1 inhibition. Hence, the combination of MRT-92 with the WEE1 inhibitor AZD-1775 showed increased antitumor activity in vitro and in iCCA xenografts compared with single treatments. These data indicate that combined inhibition of SMO and WEE1 reduces tumor burden and may represent a strategy for the clinical development of novel therapeutic approaches in iCCA.

The Interaction between hERG1 and β1 Integrins Modulates hERG1 Current in Different Pathological Cell Models

Ion channels are implicated in various diseases, including cancer, in which they modulate different aspects of cancer progression. In particular, potassium channels are often aberrantly expressed in cancers, a major example being provided by hERG1. The latter is generally complexed with β1 integrin in tumour cells, and such a molecular complex represents a new druggable hub. The present study focuses on the characterization of the functional consequences of the interaction between hERG1 and β1 integrins on different substrates over time. To this purpose, we studied the interplay alteration on the plasma membrane through patch clamp techniques in a cellular model consisting of human embryonic kidney (HEK) cells stably transfected with hERG1 and in a cancer cell model consisting of SH-SY5Y neuroblastoma cells, endogenously expressing the channel. Cells were seeded on different substrates known to stimulate β1 integrins, such as fibronectin (FN) for HEK-hERG1 and laminin (LMN) for SH-SY5Y. In HEK cells stably overexpressing hERG1, we observed a hERG1 current density increase accompanied by V_rest hyperpolarization after cell seeding onto FN. Notably, a similar behaviour was shown by SH-SY5Y neuroblastoma cells plated onto LMN. Interestingly, we did not observe this phenomenon when plating the cells on substrates such as Bovine Serum Albumin (BSA) or Polylysine (PL), thus suggesting a crucial involvement of ECM proteins as well as of β1 integrin activation.

The role of potassium channels in tumours of the GI tract: a focus on the human ether-à-go-go related gene 1 (hERG1) channels

Potassium channels are often dysregulated in tumours of the Gastro Intestinal (GI) tract. Among them, the voltage dependent channel K_V 11.1, also known as hERG1, is frequently expressed in tumours and precancerous lesions of the GI tract. In precancerous lesions, hERG1 behaves as a progression factor, contributing to identifying those patients whose lesions can progress towards true cancers. In advanced cancers, such as Colorectal and Pancreatic Cancer, a high hERG1 expression represents a negative prognostic factor, contributing to identifying high risk patients. The only exception is represented by Neuro Endocrine cancers of both the ileum and the pancreas, where hERG1 represents a positive prognostic factor for survival. In GI tumours, hERG1 can function either as a true channel, allowing outward potassium ion flux and membrane repolarisation, or in a non-canonical, non-conductive way. This occurs because, in cancer, hERG1 forms complexes with different plasma membrane and cytosolic proteins, instead of classical accessory subunits. In particular, hERG1 forms a complex with the β1 subunit of integrin receptors: the hERG1/β1 complex. Growth and chemokine receptors, small GTPases, the Phosphoinositide 3 Kinase (PI3K), as well as other ion transporters or channels are also recruited in the hERG1/β1 complex. The formation of multiprotein channel complexes represents an emerging mechanism allowing functional channel networking in both excitable and non-excitable cells. hERG1 represents a prototype of how multiprotein complexes operate in tumours, i.e. giving rise to signalling hubs which can transmit and modulate signals arising from the tumour microenvironment, hence contributing to tumour progression and malignancy. Abstract figure legend hERG1 channel is not expressed in healthy epithelial tissue while in preneoplastic lesions of the GI tract it might be expressed at different extent in altered cells (indicated in red). In some of these cells the channel might be expressed retaining at least in part its correct conductive properties (green channel with potassium ion flux, represented by the blue dots). In cancer cells hERG1 channel might be present with altered function. From a molecular point of view, a normal cell (upper right) is usually characterized by the presence of hERG1 coupled with its accessory subunit KCNE1, β1 integrin and other ion channels, transporters and receptors. On the contrary, in a cancer cell (lower right) hERG1/β1 form complexes in which other molecules, such as transporters and receptors are involved and sustain the downstream signaling regulating proliferation, motility and survival. Created with BioRender.com. This article is protected by copyright. All rights reserved.

Prognostic role of hERG1 Potassium Channels in Neuroendocrine Tumours of the Ileum and Pancreas

hERG1 potassium channels are widely expressed in human cancers of different origins, where they affect several key aspects of cellular behaviour. The present study was designed to evaluate the expression and clinical relevance of hERG1 protein in cancer tissues from patients suffering from neuroendocrine tumours (NETs) of ileal (iNETs) and pancreatic (pNETs) origin, with available clinicopathological history and follow-up. The study was carried out by immunohistochemistry with an anti-hERG1 monoclonal antibody. In a subset of samples, a different antibody directed against the hERG1/β1 integrin complex was also used. The analysis showed for the first time that hERG1 is expressed in human NETs originating from either the ileum or the pancreas. hERG1 turned out to have a prognostic value in NETs, showing (i) a statistically significant positive impact on OS of patients affected by ileal NETs, regardless the TNM stage; (ii) a statistically significant positive impact on OS of patients affected by aggressive (TNM stage IV) disease, either ileal or pancreatic; (iii) a trend to a negative impact on OS of patients affected by less aggressive (TNM stage I-III) disease, either ileal or pancreatic. Moreover, in order to evaluate whether ERG1 was functionally expressed in a cellular model of pNET, the INS1E rat insulinoma cell line was used, and it emerged that blocking ERG1 with a specific inhibitor of the channel (E4031) turned out in a significant reduction in cell proliferation.

SHMT2-mediated mitochondrial serine metabolism drives 5-FU resistance by fueling nucleotide biosynthesis

5-Fluorouracil (5-FU) is a key component of chemotherapy for colorectal cancer (CRC). 5-FU efficacy is established by intracellular levels of folate cofactors and DNA damage repair strategies. However, drug resistance still represents a major challenge. Here, we report that alterations in serine metabolism affect 5-FU sensitivity in in vitro and in vivo CRC models. In particular, 5-FU-resistant CRC cells display a strong serine dependency achieved either by upregulating endogenous serine synthesis or increasing exogenous serine uptake. Importantly, regardless of the serine feeder strategy, serine hydroxymethyltransferase-2 (SHMT2)-driven compartmentalization of one-carbon metabolism inside the mitochondria represents a specific adaptation of resistant cells to support purine biosynthesis and potentiate DNA damage response. Interfering with serine availability or affecting its mitochondrial metabolism revert 5-FU resistance. These data disclose a relevant mechanism of mitochondrial serine use supporting 5-FU resistance in CRC and provide perspectives for therapeutic approaches.

Evaluation of dental demands and needs of people experiencing homelessness in the city of Rome, Italy

OBJECTIVE

Poor oral health and oral diseases are common among people experiencing homelessness. The aim of this study was to evaluate the dental demands and needs of a population of homeless persons in the city of Rome, Italy.

PATIENTS AND METHODS

The clinical records of 165 homeless patients admitted between October 2020 and October 2021 to the dental service of the Primary Care Services of the Eleemosynaria Apostolica, Vatican City, were retrospectively reviewed. The service employed dentists to evaluate dental needs and oral conditions in patients experiencing homelessness. The main dental and oral pathological conditions were noted.

RESULTS

One hundred and sixty-five records of homeless patients were included in the study. The sample consisted in 138 males (76.97%) and 27 females (23.03%) with a mean age of 46.9 years (range 7-85 years). Acute tooth pain was reported by 132 (80%) patients, 42 (25.45%) had edentulism or missing teeth and 18 (10.91%) patients had oral lesions. Both dental and oral pathologies were intercepted and managed in secondary healthcare facilities.

CONCLUSIONS

Given the specific peculiarities of this vulnerable population, it is important to implement strategies that facilitate the access of persons experiencing homelessness to dental evaluation with a preventive and curative perspective.

Dynamics and physiological meaning of complexes between ion channels and integrin receptors: the case of Kv11.1

The cellular functions are regulated by a complex interplay of diffuse and local signals. Experimental work in cell physiology has led to recognize that understanding a cell's dynamics requires a deep comprehension of local fluctuations of cytosolic regulators. Macromolecular complexes are major determinants of local signaling. Multi-enzyme assemblies limit the diffusion restriction to reaction kinetics by direct exchange of metabolites. Likewise, close coupling of ion channels and transporters modulate the ion concentration around a channel mouth or transporter binding site. Extreme signal locality is brought about by conformational coupling between membrane proteins, as is typical of mechanotransduction. A paradigmatic case is integrin-mediated cell adhesion. Sensing the extracellular microenvironment and providing an appropriate response is essential in growth and development and has innumerable pathological implications. The process involves bidirectional signal transduction by complex supra-molecular structures that link integrin receptors to ion channels and transporters, growth factor receptors, cytoskeletal elements and other regulatory elements. The dynamics of such complexes is only beginning to be understood. A thoroughly studied example is the association between integrin receptors and the voltage-gated K+ channels Kv11.1. These channels are widely expressed in early embryos, where their physiological roles are poorly understood and apparently different from the shaping of action potential firing in the adult. Hints about these roles come from studies in cancer cells, where Kv11.1 is often overexpressed and appears to re-assume functions, such as controlling cell proliferation/differentiation, apoptosis and migration. Kv11.1 is implicated in these processes through its linking to integrin subunits.

Cetacean presence and distribution in the central Mediterranean Sea and potential risks deriving from plastic pollution

The Sardinian and Sicilian Channels are considered hotspots of biodiversity and key ecological passages between Mediterranean sub-basins, but with significant knowledge gaps about marine mammal presence and potential threats they face. Using data collected between 2013 and 2019 along fixed transects, inter and intra-annual cetacean index of abundance was assessed. Habitat suitability, seasonal hot spots, and risk exposure for plastic were performed using the Kernel analysis and the Biomod2 R-package. 661 sightings of 8 cetacean species were recorded, with bottlenose and striped dolphins as the most sighted species. The north-eastern pelagic sector, the coastal waters and areas near ridges resulted the most suitable habitats for these species. The risk analysis identified the Tunis, Palermo, and Castellammare gulfs and the Egadi Island as areas of particular risk of plastic exposure. The study represents a great improvement for cetacean knowledge in this region and contributes to the development of effective conservation strategies.

A unique circulating miRNA profile highlights thrombo-inflammation in Behçet's syndrome

Objectives

Behçet’s syndrome (BS) is a rare systemic vasculitis often complicated by thrombotic events. Given the lack of validated biomarkers, BS diagnosis relies on clinical criteria.

In search of novel biomarkers for BS diagnosis, we determined the profile of plasmatic circulating microRNAs (ci-miRNAs) in patients with BS compared with healthy controls (HCs).

Methods

ci-miRNA profile was evaluated by microarray in a screening cohort (16 patients with BS and 18 HCs) and then validated by poly(T) adaptor PCR (PTA-PCR) in a validation cohort (30 patients with BS and 30 HCs). Two disease control groups (30 patients with systemic lupus erythematosus (SLE) and 30 patients with giant cell arteritis (GCA) were also analysed.

Results

From the microarray screening, 29 deregulated (differentially expressed (DE)) human ci-miRNAs emerged. A hierarchical cluster analysis indicated that DE ci-miRNAs clearly segregated patients from controls, independently of clinical features. PTA-PCR analysis on the validation cohort confirmed the deregulation of miR-224-5p, miR-206 and miR-653-5p. The combined receiver operating characteristic (ROC) curve analyses showed that such ci-miRNAs discriminate BS from HCs (and BS with active vs inactive disease), as well as BS from patients with SLE and GCA.

The functional annotation analyses (FAAs) showed that the most enriched pathways affected by DE ci-miRNAs (ie, cell–matrix interaction, oxidative stress and blood coagulation) are related to thrombo-inflammatory mechanisms. Accordingly, the expression of the three ci-miRNAs from the validation cohort significantly correlated with leucocyte reactive oxygen species production and plasma lipid peroxidation.

Conclusions

The ci-miRNA profile identified in this study may represent a novel, poorly invasive BS biomarker, while suggesting an epigenetic control of BS-related thrombo-inflammation.

SARS-CoV-2 infection prevalence in people experiencing homelessness

OBJECTIVE

People experiencing homelessness have peculiar characteristics that make them more vulnerable to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission and to more serious forms of Coronavirus Disease 19 (COVID-19). The aim of this study was to evaluate the prevalence of SARS-CoV-2 infection in the homeless population assisted by the primary care services of the Eleemosynaria Apostolica, Vatican City.

PATIENTS AND METHODS

Persons experiencing homelessness and the volunteers assisting them were tested for COVID-19 through PCR and antigen rapid test between October 1st, 2020, and June 5th, 2021, in the clinical facilities of the Eleemosynaria Apostolica.

RESULTS

A total of 1665 subjects from 96 different countries in five continents were included in the study; age range was 1-90 years. Overall, 2315 COVID-19 tests through nasopharyngeal swab were performed; 1052 Polymerase Chain Reaction (PCR) tests and 1263 antigen rapid tests. Nearly 40% of the subjects underwent both tests (n=650, 39.04%), 402 were tested with PCR test only (24.14%) and 613 with antigen test only (36.8%). PCR tests were negative in 966 cases and positive in 86 (8.17%), while antigen tests were negative in 1205 cases and positive in 58 (4.59%). The number of positive cases varied over time, with a drastic increase during the winter months of 2020 and a progressive decrease over 2021. Among positive cases, 24.41% were symptomatic; symptoms included fever, breathing difficulties, anosmia/hyposmia, cough, headache, and diarrhea.

CONCLUSIONS

This study reported an overall prevalence of SARS-CoV-2 infection in our sample slightly above 8%. Additional data on viral genome through sequencing of SARS-CoV-2 in positive cases are of utmost importance to help identify variants and implement specific infection control measures.

Generation of an Orthotopic Xenograft of Pancreatic Cancer Cells by Ultrasound-Guided Injection

Pancreatic cancer (PCa) represents one of the deadliest cancer types worldwide. The reasons for PCa malignancy mainly rely on its intrinsic malignant behavior and high resistance to therapeutic treatments. Indeed, despite many efforts, both standard chemotherapy and innovative target therapies have substantially failed when moved from preclinical evaluation to the clinical setting. In this scenario, the development of preclinical mouse models better mimicking in vivo characteristics of PCa is urgently needed to test newly developed drugs. The present protocol describes a method to generate a mouse model of PCa, represented by an orthotopic xenograft obtained by ultrasound-guided injection of human pancreatic tumor cells. Using such a reliable and minimally invasive protocol, we also provide evidence of in vivo engraftment and development of tumor masses, which can be monitored by ultrasound (US) imaging. A noteworthy aspect of the PCa model described here is the slow development of the tumor masses over time, which allows precise identification of the starting point for pharmacological treatments and better monitoring of the effects of therapeutic interventions. Moreover, the technique described here is an example of implementation of the 3Rs principles since it minimizes pain and suffering and directly improves the welfare of animals in research.

Extracellular Signal-Regulated Kinase 5 Regulates the Malignant Phenotype of Cholangiocarcinoma Cells

BACKGROUND AND AIMS

Cholangiocarcinoma (CCA) is characterized by high resistance to chemotherapy and poor prognosis. Several oncogenic pathways converge on activation of extracellular signal-regulated kinase 5 (ERK5), whose role in CCA has not been explored. The aim of this study was to investigate the role of ERK5 in the biology of CCA.

APPROACH AND RESULTS

ERK5 expression was detected in two established (HuCCT-1 and CCLP-1) and two primary human intrahepatic CCA cell lines (iCCA58 and iCCA60). ERK5 phosphorylation was increased in CCA cells exposed to soluble mediators. In both HuCCT-1 and CCLP-1 cells, ERK5 was localized in the nucleus, and exposure to fetal bovine serum (FBS) further increased the amount of nuclear ERK5. In human CCA specimens, ERK5 mRNA expression was increased in tumor cells and positively correlated with portal invasion. ERK5 protein levels were significantly associated with tumor grade. Growth, migration, and invasion of CCA cells were decreased when ERK5 was silenced using specific short hairpin RNA (shRNA). The inhibitory effects on CCA cell proliferation, migration and invasion were recapitulated by treatment with small molecule inhibitors targeting ERK5. In addition, expression of the angiogenic factors VEGF and angiopoietin 1 was reduced after ERK5 silencing. Conditioned medium from ERK5-silenced cells had a lower ability to induce tube formation by human umbilical vein endothelial cells and to induce migration of myofibroblasts and monocytes/macrophages. In mice, subcutaneous injection of CCLP-1 cells silenced for ERK5 resulted in less frequent tumor development and smaller size of xenografts compared with cells transfected with nontargeting shRNA.

CONCLUSIONS

ERK5 is a key mediator of growth and migration of CCA cells and supports a protumorigenic crosstalk between the tumor and the microenvironment.

Neonatal Nav1.5 Protein Expression in Human Colorectal Cancer: Immunohistochemical Characterization and Clinical Evaluation

Voltage-gated Na+ channels (VGSCs) are expressed widely in human carcinomas and play a significant role in promoting cellular invasiveness and metastasis. However, human tissue-based studies and clinical characterization are lacking. In several carcinomas, including colorectal cancer (CRCa), the predominant VGSC is the neonatal splice variant of Nav1.5 (nNav1.5). The present study was designed to determine the expression patterns and clinical relevance of nNav1.5 protein in human CRCa tissues from patients with available clinicopathological history. The immunohistochemistry was made possible by the use of a polyclonal antibody (NESOpAb) specific for nNav1.5. The analysis showed that, compared with normal mucosa, nNav1.5 expression occurred in CRCa samples (i) at levels that were significantly higher and (ii) with a pattern that was more delineated (i.e., apical/basal or mixed). A surprisingly high level of nNav1.5 protein expression also occurred in adenomas, but this was mainly intracellular and diffuse. nNav1.5 showed a statistically significant association with TNM stage, highest expression being associated with TNM IV and metastatic status. Interestingly, nNav1.5 expression co-occurred with other biomarkers associated with metastasis, including hERG1, KCa3.1, VEGF-A, Glut1, and EGFR. Finally, univariate analysis showed that nNav1.5 expression had an impact on progression-free survival. We conclude (i) that nNav1.5 could represent a novel clinical biomarker ('companion diagnostic') useful to better stratify CRCa patients and (ii) that since nNav1.5 expression is functional, it could form the basis of anti-metastatic therapies including in combination with standard treatments.

Health and social conditions of children living in disadvantaged neighborhoods in the city of Rome, Italy

OBJECTIVE

The number of children living in socio-economically disadvantaged neighborhoods in developed countries is constantly growing, resulting in important implications for children's development, physical and psychological health and increased future disparities. In this study, we explored several key elements of children living in poor neighborhoods, such as demographic characteristics, access to public health assistance and school, and availability of housing and basic hygienic conditions.

PATIENTS AND METHODS

The study included 711 children aged 0-17 years referring to primary care services in the suburbs of the city of Rome, Italy.

RESULTS

Most children were born in Italy, while almost none of their parents were. Nearly 60% of the children did not have access to basic pediatric care, causing possible misdiagnosis and delayed treatment for acute and chronic conditions. A smaller percentage of the children did not have access to basic housing (8%) and hygienic facilities, such as heating, running water, and refrigerator (3.2%), leading to malnutrition, isolation and poor physical and psychological development.

CONCLUSIONS

This study confirms a critical condition for children living in disadvantaged neighborhoods, whose vulnerability is further worsened by the limited access to paediatric health assistance and, in some cases, to basic facilities with a severe impact on their physical and psychological development.

Mitochondrial oxidative metabolism contributes to a cancer stem cell phenotype in cholangiocarcinoma

BACKGROUND & AIMS

Little is known about the metabolic regulation of cancer stem cells (CSCs) in cholangiocarcinoma (CCA). We analyzed whether mitochondrial-dependent metabolism and related signaling pathways contribute to stemness in CCA.

METHODS

The stem-like subset was enriched by sphere culture (SPH) in human intrahepatic CCA cells (HUCCT1 and CCLP1) and compared to cells cultured in monolayer. Extracellular flux analysis was examined by Seahorse technology and high-resolution respirometry. In patients with CCA, expression of factors related to mitochondrial metabolism was analyzed for possible correlation with clinical parameters.

RESULTS

Metabolic analyses revealed a more efficient respiratory phenotype in CCA-SPH than in monolayers, due to mitochondrial oxidative phosphorylation. CCA-SPH showed high mitochondrial membrane potential and elevated mitochondrial mass, and over-expressed peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α, a master regulator of mitochondrial biogenesis. Targeting mitochondrial complex I in CCA-SPH using metformin, or PGC-1α silencing or pharmacologic inhibition (SR-18292), impaired spherogenicity and expression of markers related to the CSC phenotype, pluripotency, and epithelial-mesenchymal transition. In mice with tumor xenografts generated by injection of CCA-SPH, administration of metformin or SR-18292 significantly reduced tumor growth and determined a phenotype more similar to tumors originated from cells grown in monolayer. In patients with CCA, expression of PGC-1α correlated with expression of mitochondrial complex II and of stem-like genes. Patients with higher PGC-1α expression by immunostaining had lower overall and progression-free survival, increased angioinvasion and faster recurrence. In GSEA analysis, patients with CCA and high levels of mitochondrial complex II had shorter overall survival and time to recurrence.

CONCLUSIONS

The CCA stem-subset has a more efficient respiratory phenotype and depends on mitochondrial oxidative metabolism and PGC-1α to maintain CSC features.

LAY SUMMARY

The growth of many cancers is sustained by a specific type of cells with more embryonic characteristics, termed 'cancer stem cells'. These cells have been described in cholangiocarcinoma, a type of liver cancer with poor prognosis and limited therapeutic approaches. We demonstrate that cancer stem cells in cholangiocarcinoma have different metabolic features, and use mitochondria, an organelle located within the cells, as the major source of energy. We also identify PGC-1α, a molecule which regulates the biology of mitochondria, as a possible new target to be explored for developing new treatments for cholangiocarcinoma.

Harnessing the hERG1/β1 Integrin Complex via a Novel Bispecific Single-chain Antibody: An Effective Strategy against Solid Cancers

mAbs, either mono- or bispecific (bsAb), represent one of the most successful approaches to treat many types of malignancies. However, there are certain limitations to the use of full length mAbs for clinical applications, which can be overcome by engineered antibody fragments. The aim of this study was to develop a small bsAb, in the format of a single-chain diabody (scDb), to efficiently target two proteins, the hERG1 potassium channel and the β1 subunit of integrin receptors, which specifically form a macromolecular complex in cancer cells. We provide evidence that the scDb we produced binds to the hERG1/β1 complex in cancer cells and tissues, but does not bind to the hERG1 channel in nonpathologic tissues, in particular the heart. The scDb-hERG1-β1 (i) downregulates the formation of the hERG1/β1 complex, (ii) inhibits Akt phosphorylation and HIF-1α expression, and (iii) decreases cell survival, proliferation, and migration in vitro These effects only occur in cancer cells (either colon, pancreatic, or breast), but not in normal cells. In vivo, the scDb-hERG1-β1 shows a good pharmacokinetic profile, with a half-life of 13.5 hours and no general, cardiac, or renal toxicity when injected intravenously up to the dose of 8 mg/kg. The scDb-hERG1-β1 accumulates into subcutaneous xenografted tumors, arising from either colon or pancreatic human cancer cells, and induces a reduction of tumor growth and vascularization. Overall, the scDb-hERG1-β1 represents an innovative single-chain bispecific antibody for therapeutic applications in solid cancers that overexpress the hERG1/β1 integrin signaling complex.

Acceptance of COVID-19 vaccine among persons experiencing homelessness in the City of Rome, Italy

OBJECTIVE

Vulnerable populations are being more severely impacted by the ongoing pandemic, and the recent release of vaccines for Coronavirus Disease 19 (COVID-19) may offer them protection. The aim of this study was to investigate the willingness of homeless persons to be vaccinated against COVID-19; secondary aims were to analyze the immunization coverage for other conditions.

PATIENTS AND METHODS

The acceptance of COVID-19 vaccine and immunization coverage for other conditions were investigated through a form in 112 persons experiencing homelessness referring to the primary care medical services of the Eleemosynaria Apostolica, Holy See.

RESULTS

Most subjects, with a male preponderance, were willing to be vaccinated against COVID-19 (64.3%), 3.6% were unsure and 32.1% preferred not to be vaccinated. When answering questions on the immunization coverage for tuberculosis and hepatitis A and B, most subjects reported not to be vaccinated (48.2%, 56.2% and 55.3%, respectively) or did not know (33%, 28.6% and 27.7%).

CONCLUSIONS

A significant portion of our sample declared to be willing to be vaccinated against COVID-19. It would be auspicious that the recent statements from several countries on the importance to extend COVID-19 vaccination to fragile populations be followed by the distribution of the vaccine to these populations.

Transgenic mice overexpressing the LH receptor in the female reproductive system spontaneously develop endometrial tumour masses

The receptor for the luteinizing hormone (LH-R) is aberrantly over expressed in cancers of the reproductive system. To uncover whether LH-R over expression has a causative role in cancer, we generated a transgenic (TG) mouse which overexpresses the human LH-R (hLH-R) in the female reproductive tract, under the control of the oviduct-specific glycoprotein (OGP) mouse promoter (mogp-1). The transgene was highly expressed in the uterus, ovary and liver, but only in the uterus morphological and molecular alterations (increased proliferation and trans-differentiation in the endometrial layer) were detected. A transcriptomic analysis on the uteri of young TG mice showed an up regulation of genes involved in cell cycle control and a down regulation of genes related to the immune system and the metabolism of xenobiotics. Aged TG females developed tumor masses in the uteri, which resembled an Endometrial Cancer (EC). Microarray and immunohistochemistry data indicated the deregulation of signaling pathways which are known to be altered in human ECs. The analysis of a cohort of 126 human ECs showed that LH-R overexpression is associated with early-stage tumors. Overall, our data led support to conclude that LH-R overexpression may directly contribute to trigger the neoplastic transformation of the endometrium.

Ion Channels Orchestrate Pancreatic Ductal Adenocarcinoma Progression and Therapy

Pancreatic ductal adenocarcinoma is a devastating disease with a dismal prognosis. Therapeutic interventions are largely ineffective. A better understanding of the pathophysiology is required. Ion channels contribute substantially to the "hallmarks of cancer." Their expression is dysregulated in cancer, and they are "misused" to drive cancer progression, but the underlying mechanisms are unclear. Ion channels are located in the cell membrane at the interface between the intracellular and extracellular space. They sense and modify the tumor microenvironment which in itself is a driver of PDAC aggressiveness. Ion channels detect, for example, locally altered proton and electrolyte concentrations or mechanical stimuli and transduce signals triggered by these microenvironmental cues through association with intracellular signaling cascades. While these concepts have been firmly established for other cancers, evidence has emerged only recently that ion channels are drivers of PDAC aggressiveness. Particularly, they appear to contribute to two of the characteristic PDAC features: the massive fibrosis of the tumor stroma (desmoplasia) and the efficient immune evasion. Our critical review of the literature clearly shows that there is still a remarkable lack of knowledge with respect to the contribution of ion channels to these two typical PDAC properties. Yet, we can draw parallels from ion channel research in other fibrotic and inflammatory diseases. Evidence is accumulating that pancreatic stellate cells express the same "profibrotic" ion channels. Similarly, it is at least in part known which major ion channels are expressed in those innate and adaptive immune cells that populate the PDAC microenvironment. We explore potential therapeutic avenues derived thereof. Since drugs targeting PDAC-relevant ion channels are already in clinical use, we propose to repurpose those in PDAC. The quest for ion channel targets is both motivated and complicated by the fact that some of the relevant channels, for example, KCa3.1, are functionally expressed in the cancer, stroma, and immune cells. Only in vivo studies will reveal which arm of the balance we should put our weights on when developing channel-targeting PDAC therapies. The time is up to explore the efficacy of ion channel targeting in (transgenic) murine PDAC models before launching clinical trials with repurposed drugs.

Data describing the effects of potassium channels modulators on outward currents measured in human lymphoma cell lines

In the present work, applying the whole-cell patch-clamp technique in voltage clamp mode, we have investigated the effects of different drugs, such as riluzole, Psora-4 and Tram-34, on the potassium currents in four human lymphoma cell lines. We focused on outward currents mediated by two potassium channels (Kv1.3 and KCa3.1), which are known to play a key physiological role in lymphoid cells. The currents were evoked by voltage ramps ranging from -120 mV to +40 mV and the conductance of the two potassium channels was measured between +20 mV and +40 mV, both in the absence and in the presence of the specific blockers Psora-4 (Kv1.3; 1 µM) and Tram-34 (KCa3.1; 1 µM). The effect of the latter was tested after KCa3.1 channels were activated by riluzole 10 µM. Taken together, these data could be useful as an indication of the functional characteristics of the potassium channels in human lymphomas and represent a starting point for the study of potassium conductance in cellular models of these tumors.

KRAS and NRAS mutation detection in circulating DNA from patients with metastatic colorectal cancer using BEAMing assay: Concordance with standard biopsy and clinical evaluation

Patients with metastatic colorectal cancer (mCRC) are routinely screened for either K- and N-RAS to select the appropriate treatment. The present study aimed to evaluate the concordance between K- and NRAS status in the tissue (either primary tumor or metastasis) and the plasma of patients with mCRC and to identify the associations between K- and NRAS mutations in ctDNA and the clinicopathological parameters. Samples from a total of 31 patients with mCRC with measurable disease according to the Response Evaluation Criteria in Solid Tumors were analyzed. For all patients, K- and NRAS status was determined in the tissue by matrix-assisted laser desorption/ionization time of flight mass spectrometry. For the detection of RAS mutations in cell-free tumor DNA also defined as circulating tumor DNA (ctDNA), the OncoBEAM^® RAS CRC kit (Sysmex Inostics) was used. A total of 6/31 tissue samples expressed wild-type KRAS, whereas 25/31 presented mutations. In addition, 7/31 plasma samples expressed wild-type KRAS, mutations were detected in 22/31 patients, and for 2/31 patients, the test did not provide a conclusive result. A total of 24/31 patients expressed wild-type NRAS, 6/31 had mutations and 1/21 was not informative. For the KRAS mutational status, a moderate concordance (agreement, 85.18%; Cohen's k, 0.513) between the tissue and plasma analysis was observed; for NRAS, a fair agreement (agreement, 83.33%; Cohen's k, 0.242) was obtained. In conclusion, both tissue and plasma analyses should be performed for the management of patients with mCRC. To better exploit the beads, emulsions, amplification, magnetics (BEAMing) technique in the clinical setting, studies aimed at determining the RAS status to monitor therapy and during follow-up are warranted.

KV11.1 Potassium Channel and the Na+/H+ Antiporter NHE1 Modulate Adhesion-Dependent Intracellular pH in Colorectal Cancer Cells

Increasing evidence indicates that ion channels and transporters cooperate in regulating different aspects of tumor pathophysiology. In cancer cells, H⁺/HCO₃^- transporters usually invert the transmembrane pH gradient typically observed in non-neoplastic cells, which is thought to contribute to cancer malignancy. To what extent the pH-regulating transporters are functionally linked to K⁺ channels, which are central regulators of cell membrane potential (V_m), is unclear. We thus investigated in colorectal cancer cells the implication of the pH-regulating transporters and K_V11.1 (also known as hERG1) in the pH modifications stimulated by integrin-dependent cell adhesion. Colorectal cancer cell lines (HCT 116 and HT 29) were seeded onto β1 integrin-dependent substrates, collagen I and fibronectin. This led to a transient cytoplasmic alkalinization, which peaked at 90 min of incubation, lasted approximately 180 min, and was inhibited by antibodies blocking the β1 integrin. The effect was sensitive to amiloride (10 µM) and cariporide (5 µM), suggesting that it was mainly caused by the activity of the Na⁺/H⁺ antiporter NHE1. Blocking K_V11.1 with E4031 shows that channel activity contributed to modulate the β1 integrin-dependent pH_i increase. Interestingly, both NHE1 and K_V11.1 modulated the colorectal cancer cell motility triggered by β1 integrin-dependent adhesion. Finally, the β1 integrin subunit, K_V11.1 and NHE1 co-immunoprecipitated in colorectal cancer cells seeded onto Collagen I, suggesting the formation of a macromolecular complex following integrin-mediated adhesion. We conclude that the interaction between K_V11.1, NHE1, and β1 integrin contributes to regulate colorectal cancer intracellular pH in relation to the tumor microenvironment, suggesting novel pharmacological targets to counteract pro-invasive and, hence, pro-metastatic behavior in colorectal cancer.

hERG1 and HIF-2α Behave as Biomarkers of Positive Response to Bevacizumab in Metastatic Colorectal Cancer Patients

Background: In search of novel biomarkers of response to bevacizumab in metastatic colorectal cancer (mCRC), we analyzed the expression and prognostic role of several proteins related to angiogenesis. Methods: A retrospective, multicenter study on 80 surgical samples from mCRC patients treated in first line with bevacizumab plus chemotherapy was accomplished. The following proteins were analyzed by immunohistochemistry: hERG1 potassium channel, β1-integrin, pAKT, NFkB, HIF-1α, HIF-2α, p53, VEGF-A, GLUT-1, and CA-IX. Data were analyzed in conjunction with the clinicopathological characteristics of the patients, KRAS status, response to bevacizumab, and follow-up. Results: (1) All the proteins were expressed in the samples, with statistically significant associations between HIF-1α and gender, HIF-2α and left colon, hERG1 and VEGF-A, β1-integrin and HIF-2α, GLUT-1 and both HIF-1α and HIF-2α, and CA-IX and VEGF-A. (2) At the univariate analysis, positivity for hERG1, VEGF-A, and the active form of HIF-2α (aHIF-2α), and the G3 histological grade showed a positive impact on progression-free survival (PFS). (3) hERG1 and aHIF-2α maintained their positive impact on PFS at the multivariate analysis. (4) hERG1 behaved as a protective factor for PFS independently on KRAS status. Conclusions: hERG1 and aHIF-2α might help to identify patients who would benefit from bevacizumab treatment.

The hERG1 Potassium Channel Behaves As Prognostic Factor In Gastric Dysplasia Endoscopic Samples

Purpose

Gastric cancer (GC) is still a relevant health issue worldwide. The identification of prognostic factors for progression of gastric dysplasia (GD), the main pre-cancerous lesion of the intestinal-type GC, is hence mandatory.

Patients and methods

A cohort of 83 GD endoscopic samples belonging to Italian subjects was collected. hERG1 expression was evaluated by immunohistochemistry and scored 0–3, depending on the percentage of stained cells. Expression data were analysed in conjunction with clinico-pathological and survival data.

Results

hERG1 turned out to be expressed in 67.47% (56 out of 83) of the GD samples. hERG1 expression was higher in high-grade GD compared to low-grade GD (29 out of 39, 74.36% vs 27 out of 44, 61.36%), although the statistical significance was not reached (P=0.246). No association emerged between hERG1 expression and clinical features of the patients (age, gender, localization, H. pylori infection, gastritis and intestinal metaplasia). In a subset of cases for which sequential samples of gastric lesions (from GD to Early Gastric Cancer and Advanced Gastric Cancer) were available, hERG1 expression was maintained in all the steps of gastric carcinogenesis from GD onwards. A general trend to increased expression in advanced lesions was observed. hERG1 score had a statistically significant impact on both Progression-Free Survival (P=0.018) and Overall Survival (P=0.031). In particular, patients displaying a high hERG1 score have a shorter survival.

Conclusion

hERG1 is aberrantly expressed in human GD samples and has an impact on both PFS and OS, hence representing a novel prognostic marker for progression of GD towards GC of the intestinal histotype. Once properly validated, hERG1 detection could be included in the clinical practice, during endoscopic surveillance protocols, for the management of GD at higher risk of progression, as already proposed for Barrett’s oesophagus.

Data describing the effects of the Macrolide Antibiotic Clarithromycin on preclinical mouse models of Colorectal Cancer

Macrolide antibiotics, such as Clarithromycin (Cla), have been proven to exert anti-tumour activity in several preclinical models of different types of cancer. Cla can exert its anti-tumour effects through different mechanisms, e.g. by blocking the autophagic flux, inducing apoptosis or inhibiting tumour-induced angiogenesis. The clinical benefit of Cla in treating various tumours in combination with conventional treatment was confirmed in extensive clinical studies in patients suffering from non-small cell lung cancer, breast cancer, multiple myeloma and other haematological malignancies. Data regarding the anti-cancer effect of Cla on Colorectal Cancer (CRC) are still lacking. This article shares data on the in vivo efficacy of Cla in two xenograft models of CRC. Our results show that Cla treatment reduces tumour growth and increases the overall survival in CRC mouse xenograft models. Moreover, the Western blot analysis of autophagic and apoptotic markers suggests that the anti-tumour effects of Cla are related to a modulation of both cellular processes. The data suggest that it will worth consider Cla as treatment option for CRC patients.

Abstract 1216: Novel strategies in cancer immunotherapy: Harness the hERG1 β1 macromolecular complex via a new bispecific antibody and its bifunctional TRAIL

Introduction Among hindrances in cancer treatment, the lack of appropriate markers to be exploited for targeted therapy, and the need of new potential drugs are two big challenges.hERG1 potassium channels are a novel class of oncological targets and, in cancer, they are known to interact with integrins. It has been recently demonstrated that macromolecular complexes formed between hERG1 and β1 integrins selectively occurs in many types of cancer (Becchetti A et al., 2017). In this scenario, hERG1 could be exploited as a therapeutic target providing non cardiotoxic strategies aimed at blocking hERG1.

Materials and Methods A scDb, a bifunctional single-chain diabody, directed against hERG1/β1 complex, was developed via SOE-PCR methodology. Such antibody was tested on HCT116 cells in lateral motility and western blotting experiments. Moreover immunohistochemistry (IHC) was performed on metastatic colorectal cancer (mCRC) paraffin embedded samples using the scDb, an anti-hERG1 and an anti-β1 integrin. Moreover, we improved the pro-apoptotic effects of the nude hERG1/β1-scDb, developing a trifunctional recombinant protein, in which the scDb-hERG1-β1 was linked to the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL).

Results and Discussion Performing IHC on sequential sections of mCRC confirmed the specificity of the scDb for both hERG1 and β1 integrin. In vitro data provide evidences that the administering of the bispecific antibody has an impact on lateral motility. Moreover, signaling pathways are also affected by the antibody treatment, as AKT phosphorylation and HIF1α levels are decreased when the molecule is administered, suggesting a possible effect of the bispecific antibody on the VEGF-A signaling pathway, which are consistent with our previous hypothesis (Becchetti A et al., 2017) of a possible cross-talk leading to a deep impact on VEGF expression and, thus, on neoangiogenesis. Encouraging results were obtained when testing the scDb-hERG1-β1 -TRAIL fusion protein, which was capable to produce a strong induction of apoptosis in ALL cells (32.6 vs 11% at 24h; 62.4% vs 10% at 48h), with no effects on TRAIL- resistant (Panc1) tumour cells.

Conclusions scDb-hERG1/β1 could be used as a potential new therapeutic tool for cancer patients’ treatment as well as for early molecular diagnosis. In fact, the selective expression of hERG1/β1 complex in cancer cells and its role in angiogenesis and cancer progression suggests that a molecule selectively targeting the complex will be an invaluable tool for cancer treatment. In this view, we have recently licensed a patent which will be exploited with the final aim to undergo clinical trials. Becchetti A, et al. (2017) Science Signaling 10(473). Patent. Inventors: Arcangeli A, Duranti C. et al. Patent Ref: 102017000083637

Citation Format: Claudia Duranti, Jessica Iorio, Stefano Coppola, Giulia Petroni, Tiziano Lottini, Lara Magni, Elena Lastraioli, Annarosa Arcangeli. Novel strategies in cancer immunotherapy: Harness the hERG1 β1 macromolecular complex via a new bispecific antibody and its bifunctional TRAIL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1216.

Replacement of the Thiosugar of Auranofin with Iodide Enhances the Anticancer Potency in a Mouse Model of Ovarian Cancer

In recent years, a few successful attempts were made to repurpose the clinically approved antiarthritic gold drug, Auranofin (AF), as an anticancer agent. The present study shows that the iodido(triethylphosphine)gold(I) complex, (Et ₃ PAuI hereafter)-an AF analogue where the thiosugar ligand is simply replaced by one iodide ligand-manifests a solution chemistry resembling that of AF and exerts similar cytotoxic and proapoptotic effects on A2780 human ovarian cancer cells in vitro. However, when evaluated in a preclinical orthotopic model of ovarian cancer, Et ₃ PAuI produces a far superior anticancer action than AF inducing a nearly complete tumor remission. The highly promising in vivo performances here documented for Et ₃ PAuI warrant its further evaluation as a drug candidate for ovarian cancer treatment.

The Activity of Kv 11.1 Potassium Channel Modulates F-Actin Organization During Cell Migration of Pancreatic Ductal Adenocarcinoma Cells

Cell migration exerts a pivotal role in tumor progression, underlying cell invasion and metastatic spread. The cell migratory program requires f-actin re-organization, generally coordinated with the assembly of focal adhesions. Ion channels are emerging actors in regulating cell migration, through different mechanisms. We studied the role of the voltage dependent potassium channel K_V 11.1 on cell migration of pancreatic ductal adenocarcinoma (PDAC) cells, focusing on its effects on f-actin organization and dynamics. Cells were cultured either on fibronectin (FN) or on a desmoplastic matrix (DM) with the addition of a conditioned medium produced by pancreatic stellate cells (PSC) maintained in hypoxia (Hypo-PSC-CM), to better mimic the PDAC microenvironment. K_V11.1 was essential to maintain stress fibers in a less organized arrangement in cells cultured on FN. When PDAC cells were cultured on DM plus Hypo-PSC-CM, K_V11.1 activity determined the organization of cortical f-actin into sparse and long filopodia, and allowed f-actin polymerization at a high speed. In both conditions, blocking K_V11.1 impaired PDAC cell migration, and, on cells cultured onto FN, the effect was accompanied by a decrease of basal intracellular Ca²⁺ concentration. We conclude that K_V11.1 is implicated in sustaining pro-metastatic signals in pancreatic cancer, through a reorganization of f-actin in stress fibers and a modulation of filopodia formation and dynamics.

Ion Channel Conformations Regulate Integrin-Dependent Signaling

Cell-matrix adhesion determines the choice between different cell fates and is accompanied by substantial changes in ion transport. The greatest evidence is the bidirectional interplay occurring between integrin receptors and K⁺ channels. These proteins can form signaling hubs that regulate cell proliferation, differentiation, and migration in normal and neoplastic tissue. Recent results show that the physical interaction with integrins determines the balance of the open and closed K⁺ channel states, and individual channel conformations regulate distinct downstream pathways. We propose a model of how these mechanisms regulate proliferation and metastasis in cancer cells. In particular, we suggest that the neoplastic progression could be modulated by targeting specific ion channel conformations.

Peptides and small molecules blocking the CXCR4/CXCL12 axis overcome bone marrow‑induced chemoresistance in acute leukemias

Notable advances in treatment have been made and increases in the cure rates of pediatric leukemia have been achieved. However, the majority of children with relapsed disease are not expected to survive, with chemotherapy resistance acting as the principal cause of treatment failure. Interaction between leukemic cells and the bone marrow microenvironment is the primary cause of relapse. It was identified that a multi‑protein membrane complex, formed by potassium voltage‑gated channel subfamily H member 2 (hERG1) channels, the β1 integrin subunit and the stromal cell‑derived factor 12 (CXCL12) receptor, C‑X‑C chemokine receptor type 4 (CXCR4), exerts a role in mesenchymal stromal cell (MSC)‑mediated chemoresistance in pediatric leukemias. hERG1 blockade was able to overcome chemoresistance in vitro and in vivo. As an alternative strategy to overcome chemoresistance, the present study evaluated the effects of novel tools targeting the CXCR4/CXCL12 axis. The analysis of CXCL12 structural dynamics was used for the selection of a peptide (4‑1‑17) and a small molecule (8673), which interact with a transient hot spot, identified by a dynamic drug design approach. The present findings indicated that peptide 4‑1‑17 and small molecule 8673 inhibited leukemia cell proliferation and induced a pro‑apoptotic effect, which was not reduced by the presence of MSCs. The combined treatment with 4‑1‑17 and 8673 had a stronger pro‑apoptotic effect, particularly on cells cultured on MSCs in normoxic and hypoxic conditions, and was able to overcome MSC‑induced resistance to cytarabine. Overall, the targeting of CXCL12 and the ensuing inhibition of the CXCR4/CXCL12 axis may be proposed as an alternative strategy to overcome chemoresistance in leukemia.

Postnatal Changes in K+/Cl- Cotransporter-2 Expression in the Forebrain of Mice Bearing a Mutant Nicotinic Subunit Linked to Sleep-Related Epilepsy

The Na+/K+/Cl- cotransporter-1 (NKCC1) and the K+/Cl- cotransporter-2 (KCC2) set the transmembrane Cl- gradient in the brain, and are implicated in epileptogenesis. We studied the postnatal distribution of NKCC1 and KCC2 in wild-type (WT) mice, and in a mouse model of sleep-related epilepsy, carrying the mutant β2-V287L subunit of the nicotinic acetylcholine receptor (nAChR). In WT neocortex, immunohistochemistry showed a wide distribution of NKCC1 in neurons and astrocytes. At birth, KCC2 was localized in neuronal somata, whereas at subsequent stages it was mainly found in the somatodendritic compartment. The cotransporters' expression was quantified by densitometry in the transgenic strain. KCC2 expression increased during the first postnatal weeks, while the NKCC1 amount remained stable, after birth. In mice expressing β2-V287L, the KCC2 amount in layer V of prefrontal cortex (PFC) was lower than in the control littermates at postnatal day 8 (P8), with no concomitant change in NKCC1. Consistently, the GABAergic excitatory to inhibitory switch was delayed in PFC layer V of mice carrying β2-V287L. At P60, the amount of KCC2 was instead higher in mice bearing the transgene. Irrespective of genotype, NKCC1 and KCC2 were abundantly expressed in the neuropil of most thalamic nuclei since birth. However, KCC2 expression decreased by P60 in the reticular nucleus, and more so in mice expressing β2-V287L. Therefore, a complex regulatory interplay occurs between heteromeric nAChRs and KCC2 in postnatal forebrain. The pathogenetic effect of β2-V287L may depend on altered KCC2 amounts in PFC during synaptogenesis, as well as in mature thalamocortical circuits.

hERG1 channel expression associates with molecular subtypes and prognosis in breast cancer

Background

Breast cancer (BC) is the most frequent malignancy among females worldwide. Despite several efforts and improvements in early diagnosis and treatment, there are still tumors characterized by an aggressive behavior due to unfavorable biology, thus quite difficult to treat. In this view, searching for novel potential biomarkers is mandatory. Among them, in the recent years data have been gathered addressing ion channel as important players in oncology.

Methods

A retrospective pilot study was performed on 40 BC samples by means of immunohistochemistry in order to evaluate hERG1 potassium channels expression in BC.

Results

We provide evidence that hERG1 is expressed in all the BC samples analyzed. hERG1 expression was significantly associated with molecular subtype with the highest expression in Luminal A and the lowest in basal-like tumors (p = 0.001), tumor grading (the highest hERG1 expression in well-moderate differentiated tumors, p = 0.020), estrogen receptors (high hERG1 expression in ER-positive samples, p = 0.008) and Ki67 proliferative index (high hERG1 scoring in samples with low proliferative index, p = 0.038). Also, a p value close to significance was noticed for the association between hERG1 and HER2 expression (p = 0.079). At the survival analysis, patients with high hERG1 expression turned out to have a longer progression-free survival, although statistical significance was not reached (p = 0.195). The same trend was observed analyzing local relapse free-survival (LRFS) and metastases-free survival (MFS): patients with higher hERG1 scoring had longer LRFS and MFS (p = 0.124 and p = 0.071, respectively).

Conclusions

The results of this pilot study provide the first evidence that the hERG1 protein is expressed in primary BC, and its expression associates with molecular subtype. hERG1 apparently behaves as a protective factor, since it contributes to identify a subset of patients with better outcome. Overall, these data suggest that hERG1 might be an additional tool for the management of BC, nevertheless further investigations are warranted to better clarify hERG1 role and clinical usefulness in BC.

Abstract 183: HERG1 potassium channels perturb the β1 integrins mediated force transduction machinery in pancreatic cancer

Ion channels regulate cell proliferation, differentiation, and migration in normal and neoplastic cells through cell-cell and cell-extracellular matrix (ECM) transmembrane receptors called integrins. K+ flux through the human ether-à-gogo-related gene 1 (hERG1) channel shapes action potential firing in excitable cells such as cardiomyocytes. Its abundance is often aberrantly high in human tumors, including the pancreatic ductal adenocarcinoma (PDAC). We recently demonstrated that the direct interaction of β1 integrins with hERG1 channels in cancer cells stimulated distinct signaling pathways that depended on the conformational state of hERG1 and affected different aspects of tumor progression [1].

We hypothesized that hERG1 channels compromise the PDAC mechano-reciprocity, the ability to dynamically respond to externally applied forces by exerting forces, which enhances invasion and compromises treatment.

Using elastic micropillar arrays of varying stiffness (20-150 kPa) [2], we quantified the β1-integrin mediated forces exerted by PANC-1 cells. Micropillars coating with collagen and/or fibronectin derived peptides allowed us to direct cell surface receptor binding specificity (i.e. α2β1 and α5β1 integrins). Independently of the substrate coating, PANC-1 cells exerted higher forces as a function of substrate stiffness, as already demonstrated for other cell types. Remarkably, the disruption of the β1/hERG1 interaction through E4031 inhibition of hERG1 channels resulted in a significant increase in the detected cellular forces by ~20%, accompanied by an increase of focal adhesion areas as demonstrated by staining with vinculin.

Our results suggest that, in addition to alter distinct signaling pathways and tumor progression [1], the direct interaction of β1 integrins and hERG1 channels perturbs the force transduction machinery. These findings encouraged us to develop bispecific antibodies (scDb, single-chain diabody) binding to the β1/hERG1 complex that are now being validated in PDAC cell lines. In particular, we have developed a bispecific antibody (scDb-β1/hERG1) [3], which is composed by the variable domains (VH and VL chains) of monoclonal antibodies binding two different antigens, hERG1 and β1 integrin. Data obtained from in vitro studies demonstrates that the scDb antibody impacts cell viability and migratory behavior in Mia PaCa-2 cell lines, holding promises for translational impact after a further validation in vivo as a novel candidate in cancer therapeutics.

[1] Becchetti et al. Science Signaling (2017), 10 (473), eaaf3236.

[2] van Hoorn et al. Nano Lett (2014), 14, 4257-4262.

[3] Patent: “Novel antibodies”. Inventors: Annarosa Arcangeli, Claudia Duranti, Silvia Crescioli, Laura Carraresi. Patent Deposit: July 2017. Patent Ref: 102017000083637 (University of Florence).

Citation Format: Stefano Coppola, Claudia Duranti, Annarosa Arcangeli, Thomas Schmidt. HERG1 potassium channels perturb the β1 integrins mediated force transduction machinery in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 183.